The following books are excellent professional resources for any teacher, not just English teachers. I've linked the Amazon page for each book simply for convenience.
They Say, I Say: The Moves That Matter in Academic Writing
By Gerald Graff and Cathy Berkenstein. Contains templates that students can use immediately in their writing to improve the sound and flow of persuasive writing.
Teaching English in Middle and Secondary Schools
By Katherine McKnight. Contains lots of tips and techniques to use immediately. One of the nation's foremost authorities for grades 6-12 literacy.
Ready-to-Use English Workshop Activities for Grades 6-12: 180 Daily Lessons Integrating Literature, Writing & Grammar Skills
By Mary Ellen Ledbetter. Accessible handouts and worksheets for improving student writing. This author completely changed the way I teach writing.
A Pocket Style Manual
By Diana Hacker and Nancy Sommers. A quick research-writing reference book for students. Includes APA, Chicago and MLA styles.
The Curse of the Good Girl
By Rachel Simmons. Addresses the struggles that girls deal with in today's society because of all the conflicting messages.
How to Read Literature Like a Professor
By Thomas Foster. Hilarious and insightful.